Limb passive heating to 35°C and 40°C significantly increased antegrade shear rate and altered retrograde shear rate in brachial and femoral arteries compared to 30°C controls (p<0.0001).
Does limb passive heating improve conduit artery shear rate and maintain thermal comfort in healthy participants?
Limb passive heating targeting a skin temperature of approximately 38°C effectively improves conduit artery shear rate while maintaining thermal comfort.
p-value: p=<0.0001
Cardiovascular disease remains the leading cause of mortality. One reason is vascular dysfunction leading to pathological shear rate pattern. Limb passive heating (LPH) is a non-pharmacological intervention, improving vascular health by enhancing shear rate. As LPH is intended for long-term application, it is essential to identify a tolerable heating intensity that effectively reduces retrograde and increases antegrade shear rate without causing thermal discomfort. This study aimed to determine an LPH intensity that balances effective shear rate levels with thermal comfort. In 15 healthy participants (26 ± 3 years), LPH was applied to the right arm and leg targeting skin temperatures of resting baseline, 35°C and 40°C, while the contralateral limbs were maintained at 30°C as controls. After 10 min of steady-state heating, brachial and superficial femoral retro-, and antegrade shear rates, and local thermal comfort were assessed. Brachial artery: antegrade shear rate (35°C, p = 0.006; 40°C, p < 0.0001) increased, retrograde shear rate (p = 0.006) reduced at 40°C, and local arm thermal comfort was 8 ± 1. Femoral artery: antegrade shear rate (35°C, p < 0.0001; 40°C, p < 0.0001) and retrograde shear rate (35°C, p = 0.001; 40°C, p < 0.0001) altered significantly compared to controls, with local leg thermal comfort at 9 ± 1. These findings suggest through statistical interpolation, on average a skin temperature of approximately 38°C is perceived as thermally comfortable during acute LPH.
Schabbehard et al. (Mon,) conducted a other in Healthy (n=15). Limb passive heating vs. Contralateral limbs maintained at 30°C was evaluated on Brachial and superficial femoral retro- and antegrade shear rates, and local thermal comfort (p=<0.0001). Limb passive heating to 35°C and 40°C significantly increased antegrade shear rate and altered retrograde shear rate in brachial and femoral arteries compared to 30°C controls (p<0.0001).